Emerging Insights On Surgical Correction Of Laterally Deviated Toes

Given the myriad of possible etiologies for deviated second or third toes, it is valuable to have a range of treatment options. This author offers a closer look at surgical management and current concepts with the Weil distal oblique metatarsal osteotomy, the extensor digitorum brevis tendon transfer and soft tissue balancing of the lesser metatarsophalangeal joint.

One of the most complex deformities involves transverse plane deviation of the lesser toes. The medially deviated second toe has received much attention, especially when it is combined with sagittal plane contracture (i.e., crossover toe).5,8 However, lateral deviation of the second and/or third toe represents commonly seen but infrequently discussed problems.7,8

After diagnosing lateral deviation of the second and/or third toe, one can choose between symptomatic relief care, conservative measure accommodation and/or reduction of the deformity, or surgical intervention. When it comes to symptomatic relief care, options include cryotherapy, non-narcotic analgesic/anti-inflammatory, topical liniment or decreased activities. In regard to accommodation and/or reduction of the deformity, conservative measures include tape or commercially available splintage, metatarsal pad or insole use, and/or stiff-soled shoes. One may also consider surgical intervention options such as metatarsal osteotomy, digital arthrodesis and soft tissue procedures.7,9-12

Although not all inclusive, this article will focus on the lateral transposition Weil distal oblique metatarsal osteotomy, the extensor digitorum brevis tendon transfer, and soft tissue balancing of the lesser metatarsophalangeal joint (MPJ) for surgical correction of the laterally deviated second and/or third toes.

Keys To Determining The Metatarsal Length Pattern

When deciding on operative intervention, it is critical that the surgeon determines the metatarsal length pattern. Radiographic analysis is the gold standard by which one determines the metatarsal length parabola.

Bojsen-Møller conducted a mechanical study and determined the most mechanically effective metatarsal length pattern.13 This pattern is one in which the second metatarsal is the longest, the third is the same length as the first, the fourth is shorter than the third, and the fifth is shorter than the fourth (i.e., 2>1=3>4>5).

Maestro and colleagues have defined the normal relative metatarsal length parabola according to the “Maestro line.”14 This refers to the line passing from the center of the fibular sesamoid, perpendicular to the longitudinal bisection of the second metatarsal, and through the fourth metatarsal head. In a series of 40 “normal” feet, employing the aforementioned Maestro line, Maestro and colleagues determined the ideal relative metatarsal length parabola.15 This length is when the first metatarsal is equal to or 2 mm shorter than the second metatarsal, the third metatarsal is 4 mm shorter than the second, the fourth metatarsal is 6 mm shorter than the third metatarsal, and the fifth metatarsal is 12 mm shorter than the fourth metatarsal (i.e., 1=2>3>4>5 or 13>4>5).

Therefore, based on the available literature, the “ideal” relative metatarsal length pattern appears to be when the first and second metatarsals are equal in length, and a gentle taper exists between the remaining metatarsals (1=2>3>4>5).

One should clearly understand that proper metatarsal relationships involve both the relative length of the metatarsals and the sagittal plane relationship. This should consist of each metatarsal being oriented parallel to one another on the weightbearing surface during the stance and propulsive phases of the gait cycle.2,7,12 One can best determine the relative sagittal plane relationship between the metatarsals on a medial oblique radiograph.7

Pertinent Insights On The Weil Distal Oblique Metatarsal Osteotomy

The Weil distal oblique metatarsal osteotomy has received much attention regarding central metatarsal abnormalities.16-27 Surgeons have even applied this technique to the hand for metacarpal deformities.28 The Weil distal oblique metatarsal osteotomy involves minimal soft tissue dissection, is easy to perform, allows precise placement of the plantar capital fragment, can involve multiple modifications, is inherently stable in design requiring a minimal amount of internal fixation, and allows for immediate guarded weightbearing.7,16,17

In this procedure, the surgeon would perform a dorsal linear incision extending from the distal one-third of the lesser metatarsal to the base of the proximal interphalangeal joint of the associated digit. When performing surgery on adjacent metatarsals, one would place the incision over the intermetatarsal space instead.

Regardless of placement, deepen the incision directly through the skin, superficial fascia and adipose tissue to the level of the capsule and periosteum overlying the lesser MPJ. Several approaches to the lesser MPJ are possible and include: (1) splitting the natural junction between the extensor digitorum longus and brevis when there is no transverse plane toe deviation; (2) direct medial incision when there is lateral toe deviation; and (3) direct lateral incision when there is medial toe deviation.7,16,17

Regardless of approach, after you incise the extensor tendon complex, reflect the capsule and periosteum using a surgical scalpel and periosteal elevator in order to expose the dorsal, medial and lateral aspects of the lesser metatarsal head and neck. Begin the osteotomy at a level 2 mm below the dorsal articular cartilage of the lesser metatarsal head. Angle the osteotomy proximally in such a manner as to extend it to the junction of the distal and middle third of the metatarsal. This junction is just proximal to the plantar metaphyseal-diaphyseal junction and is termed the “axilla” or “cul-de-sac” of the lesser metatarsal.7,16,17 This angle approximates a 10- to 15-degree plantar angle in comparison with the longitudinal axis of the metatarsal, which in turn is plantar declinated in relation to the weightbearing surface of the foot.7,16,17

The surgeon would perform a “pure” Weil osteotomy by completing the osteotomy through the plantar diaphysis, creating two separate osseous segments. The plantar capital fragment will readily migrate proximally and, interestingly, almost always “settles” at the desired level of shortening. However, one should verify this with intraoperative image intensification to properly determine the appropriate degree of shortening to balance the metatarsal parabola as I previously described.

If one performs more than 3 mm of shortening for any of the central metatarsals, remove a small “slice” bone from the plantar capital fragment since it has a larger bone mass than the remaining metatarsal shaft.16,19 Then hold the plantar capital fragment in full apposition with either a small “scoop type” elevator or with the index finger from your non-dominant hand. Provide dorsally directed pressure at the proximal extent of the osteotomy and fixate this with one or two small diameter non-lag screws and/or threaded Kirschner wires. One can then gently resect any redundant dorsal osseous prominence with a rongeur to a normal anatomical configuration.

A Closer Look At Modifications To The Weil Metatarsal Osteotomy Technique

Several modifications to the Weil metatarsal osteotomy exist. These include: “tilt-up,” “tilt-down,” medial transposition and lateral transposition of the plantar capital fragment.16,22,26

For the purpose of this article, I will focus on the lateral transposition Weil distal oblique metatarsal osteotomy modification since this is indicated in the presence of a laterally deviated toe.16,22

One would perform the lateral transposition Weil metatarsal osteotomy as I described above with the exception of transposing the plantar capital fragment in a lateral direction up to two-thirds the width of the remaining metatarsal shaft. Through lateral transposition of the plantar capital fragment, the toe will assume a more medial position similar to the effect that lateral transposition of the first metatarsal head has on the reduction of the hallux at the first MPJ during hallux valgus correction.16 Then hold the plantar capital fragment in full apposition and fixate it as I described above. Following that, one may gently resect any redundant dorsal osseous prominence with a rongeur.

Supplemental soft tissue balancing of the lesser MPJ following the lateral transposition Weil distal oblique metatarsal osteotomy consists of vertical incision of the medial capsule and reinforcement of the lateral capsule. If necessary, one may also perform a partial release of the medial plantar plate off the base of the proximal phalanx.7,29

The most efficacious technique to correct lateral toe deviation following supplemental soft tissue balancing and lateral transposition Weil distal oblique metatarsal osteotomy is the extensor digitorum brevis tendon transposition.33,34 The technique involves transection of the extensor digitorum brevis tendon proximally and rerouting of the tendon on the medial side of the MPJ from distal to proximal and deep to the deep transverse intermetatarsal ligament. Following the transfer, surgeons can reattach the tendon to itself, tenodese the tendon to the medial aspect of the extensor digitorum longus tendon, weave the tendon through the medial capsule and periosteum, or transfer the tendon through a drill hole in the metatarsal shaft.7,33,34

Following irrigation of the surgical site, hold the associated lesser toe in an over-corrected, plantarflexed and medially deviated position, and appose the extensor tendon complex with absorbable sutures. The surgeon can then approximate the remaining deep tissues and skin edges using his or her preferred technique.

The surgical correction of laterally deviated toes I have described here allows for immediate weightbearing in a bulky, well-padded surgical dressing and postoperative shoe. Patients wear a “sling type” toe brace (such as a Budin splint) for 12 months to maintain the digit in a plantarflexed posture and limit the potential for secondary dorsal scar tissue induced migration of the digit.

Additionally, one should instruct the patient to perform active and passive plantarflexion home physical therapy multiple times throughout the day to further prevent an extensus contracture. This also strengthens the intrinsic musculature and flexor apparatus for long-term digit stabilization.

Since the techniques I have described are inherently stable, once one has removed the surgical dressings, the patient immediately can wear a gym shoe to limit postoperative edema. Once this subsides, patients are allowed to return to their shoe gear of choice.16,17 Occasionally, due to the transposition of the metatarsal head and small bone surface for contact, rotation of the metatarsal head or fracture of the dorsal shelf of bone occurs. However, loss of correction or the need to revise the surgery is exceptionally rare. Patients are allowed to return to activities as soon as their pain is tolerable and if they see a podiatrist at regular intervals to assess the incision site healing and any other related issues.

In Conclusion

Surgical correction of laterally deviated toes focuses on the lateral transposition Weil distal oblique metatarsal osteotomy coupled with soft tissue balancing of the MPJ and extensor digitorum longus tendon transfer to aid in transverse plane deformity correction at the lesser MPJ level. Additionally, one can correct the individual deformities of each toe and metatarsal simultaneously (i.e., medially deviated second toe and lateral deviated third toe), employing these techniques through the same incision.

Surgeons should emphasize proper preoperative clinical and radiographic analysis, attention to surgical technique as well as appropriate and aggressive postoperative splinting and physical therapy in each instance to optimize outcomes.

Dr. Roukis is attending staff in the Department of Orthopaedics, Podiatry, and Sports Medicine at Gundersen Lutheran Medical Center in La Crosse, Wis. He is a Fellow and the Secretary-Treasurer on the Board of Directors of the American College of Foot and Ankle Surgeons.

For related articles, see “How To Conquer Crossover Second Toe Syndrome” in the August 2002 issue of Podiatry Today or “Essential Insights On Tendon Transfers For Digital Dysfunction” in the April 2010 issue.